Should We Prepare for the Encounter with Extraterrestrial Civilisations?

Abstract

It was 70 years ago last year that Enrico Fermi articulated his famous paradox: if there were extraterrestrial civilisations, we should have already met them. There have been many attempts in recent decades to resolve the contradiction, but hardly any to clarify the strategies which ensue for humanity from the individual explanations – even though such an event may result in our annihilation. Do extraterrestrials represent a threat? What should we do to survive our encounter? The answer to these questions depends largely on what explanations we consider likely for the problem raised by Fermi. The present study does not undertake to exhaustively analyse, or even list the myriad possible responses proposed in recent decades, it shall confine itself to sorting the most important into four broad categories and, on that basis, to examine the course of action required by the various assumptions in order to safeguard the security of mankind.